Method of and apparatus for measuring and recording gas interchangeability



May 7, 19.46.'

E. x. SCHMIDT 2,399,830 METHOD OF AND APPARATUS FOR MEASURING AND RECORDING GAS INTERGHANGEABILTY Filed April 24, 1944 2 Sheets-Sheet l May 7, 1946.

E x. SCHMIDT METHOD OF ANb APPARATUS FOR MEASURING AND RECORDING GAS INTERCHANGEABILTY Filed April 24, 1944 2 Sheets-Sheet 2 Patented May 7, 1946 METHOD OF AND APPARATUS FOR MEASUR- IN G AND RECORDING GAS IN TERCHANGE- ABILITY Edwin X. Schmidt, Nash let-Hammer, tion of Delaware ota, Wis., assignor to Cut- Inc., Milwaukee, Wis., a corpora- Application April 24, 1944, Serial No. 532,434

16 Claims.

This invention relates to improvements in methods of and apparatus for measuring and recording gas interchangeability.

With respect to gas interchangeability, it may be pointed out that two gases which would be entirely or completely interchangeable would have physical and chemical characteristics such that interchange or substitution one for the other on any gas burning appliance would in nowise change or affect the performance of the gas burning appliance. Such an ideal condition will seldom be obtainable, due to the large number of variable factors affecting combustion, the various uses made of the results of combustion, and the varying efiects of the properties of gases on different types of burners.

For a practical consideration of the gas interchangeability problem, it must be appreciated that complete interchangeability is not attainable, and the substitution of one gas or gases for another must necessarily be a compromise; the extent of such compromise depending upon the types of gases involved; and the criterion of interchangeability being somewhat arbitrary in nature, unless the specific type of gas-burning equipment involved and the combustion requirements are known. I

In the general distribution of gas to cormnunities, such as in city gas distribution systems, there are certain general combustion characteristic requirements which determine Whether consumer appliances will function in a satisfactory manner. The principal properties which effector control satisfactory performance might be individually measured and determined. As the result of extensive experiments I have found that such properties are: total heating value per standard cubic foot of the particular gas, the density thereof, the percentage value of primary air required to produce a fixed ignition velocity, and the relative volume of primary air-gas mixture producing such ignition velocity when the volume of gas in said mixture is determined by a fixed pressure For interchangeability on domestic appliances other combustion characteristics are of much less importance.

These more important properties of a gas can be combined into a single factor, or property of a gas, which I will herein characterize as the interchangeability factor K. Toprovide for assignment of this factor K to any gas without relating the factor to asecond gas, the property of .relative volume of primary air is, in the value K, related to a type of as f known characdrop across a fixedrestriction.

teristics as a basic gas, so thatgases of substantially identical K values will produce satisfactory combustion on average domestic consumer appliances.

A primary object of thepresent invention is to provide a method of and apparatus for indicating and/or recording thi interchangeability factor or property of a gas.

Another object is to provide for calibration of the device in some standardized scale which may he graduated in numbers which are of significance.

Another object is to provide means enabling adjustment of the device to. meet the requirements of each particular installation.

Another object is to provide simple means affording adjustment of the range coverage of the device to suit the requirements of a given installation.

Other objects and advantages of the invention will hereinafter appear.

The accompanying drawings illustrate certain embodiments of my invention which will now be described, it being understood that the embodiments illustrated are susceptible of modification in respect of certain structural details thereof without departing from the scope of the appended claims.

In the drawings,

Figure 1 is a view, partly in elevation and partly in vertical section, of a gas interchangeability measuring device constructed in accordance with my invention; certain of the parts to provide for recording of the ascertained value being also illustrated.

Fig. 2 is a sectional view,

Fig.1. l

,Fig. 3 is a fragmentary sectional view ,of a

burner tip like that shown in Fig. 1, but illustrating a modified form of probe for cooperation with the inner cone of the burner flame.

Fig. 4 is a front elevational view of one form of recorder which may be utilized in conjunction with the device of Fig. 1, and,

F 5 illustrates schematically and dia rammatically a system, embodying 'a modified form of the device of Fig. 1, to afford distant indication and recordation of the aforementioned interchangeability characteristicsK of a gas; it being understood that the burner parts not illustrated in'Fig. 5 may be identical with those shown in Fig. 1.

It maybe pointed out that most domestic apon the lin 22 of pliances, like the burner shown in Fig. 1, have an inherent rate of gas flow depending upon the pressure across the jet, the size of the jet, and the density of the gas. Thus, the relative rate of gas flow may be expressed as 1/\ d, where d is the density of the gas. The momentum of the gas, which tends to induce a flow of air, i independent of the composition of the gas; depending only upon the gas pressure, and the size and efficiency of the jet. Inasmuch as the jet efficiency does not change appreciably with change in gas composition, and inasmuch as most of the momentum of the gas is transmitted to the gas and primary air and dissipated in the primary air chutes, burners of this type will induce substantially the same amount of air regardless of the gas composition; which fact has been substantiated by numerous tests.

The amount of air required for complete combustion of the gas passing through the jet is dependent upon the rate of gas flow, the heating value per unit volume of the gas, and the quantity of air required per unit of heat in the particular gas. The theoretical required rate oi flow of air may thus be defined as (Hp=l/ /d) (heating value) (a) where d is the density, heating value is in B. t. u. per standard cubic foot, and a is the quantity of air required per B. t. u.

It is a well known fact that domestic gas burning appliances are almost invariably adjusted so that the induced primary air is of a value lower than 100 per cent. In fact most domestic appliances are so adjusted that the percentage of primary air is at a value which produces an ignition velocity substantially lower than the value of primary air which will produce the so-called maximum ignition velocity of the particular gas. Thus most burners with an increase in the percentage value of primary air will produce a higher ignition velocity and an inner cone of smaller size. Moreover, in practice the burners are usually adjusted for a percentage value of primary air which produces approximately the same ignition velocity regardless of the type of gas on which the burner is being operated when the adjustment is made. The result is that on burners supplied with so-called fast burning gases the usual practice is to lower the percentage of primary air and to increase the percentage of primary air for slow burning gases, so that inner cone sizes will be about the same. This fact is important in respect of the matter of gas interchangeability, for it is an inherent characteristic of gases that, within this normal range of burner adjustment, a fixed increment in the percentage value of primary air changes the ignition velocity by a fixed percentage change for most gases; so that gases which are interchangeable in respect of inner cone size with one particular burner adjustment will also be interchangeable for another particular adjustment within the normal range of burner adjustment as used in common practice.

For any one gas the percentage value of primary air'which will produce a fixed ignition velocity (which velocity should preferably be a value commonly obtained in domestic appliances) is fixed or constant. For example, to obtain an ignition velocity of 8% of the maximum ignition velocity of hydrogen, the percentage value of primary air for hydrogen is 13%; for propane it is 65%; and for methane it is 76%.

On a burner as commonly adjusted the percentage value of primary air will thus approximately correspond with the percentage value oi primary air required for the particular gas. The flow of primary air into the burner may then be determined from the theoretical air requirement of the particular gas for which the burner was adjusted; namely, the value (Hp) (a). For ex ample, with a 580 B. t. u. gas of .59 density, the amount of air required per B. t. u. is .0089 cubic foot. The theoretical relative air requirement would be: 580/\ .59) (.0089); and if this gas required 56% air for 8% ignition velocity the primary air fl ow in the burner may be taken as: .56 (580/\ .59) (.0089).

If another or substitute gas is then supplied to the same burner the rate of primary air flow will remain substantially the same; and in order to again obtain the same 8% of ignition velocity the relative theoretical air requirement of the substitute gas must be such that the percentage value of primary air supplied with the new gas will correspond to the percentage value of primary air required for the new gas to provide 8% ignition velocity.

Propane and air may be mixed to form a gas having these characteristics. 'Ihus, propane and air can be mixed to form a gas in which the quantity of the air flow divided by the relative theoretical air requirement, and multiplied by gives the percentage value of primary air required to produce an ignition velocity of 8%; and a propane-air mixture of this composition would produce the same ignition velocity as was produced by the gas for which the burner was originally adjusted. This propane-air mixtur would not necessarily produce the same size inner cone, or same flame stability, for both are determined by the ignition velocity and the velocity of the primary air-gas mixture issuing from the burner port. The latter velocity is not necessarily the same for the propane-air mixture (producing the same ignition velocity as the gas for which the burner was adjusted) as it is for such other gas.

In the example aforementioned the port velocity would be lower on the propane-air mixture due to the higher density of the gas. It will be apparent to those skilled in the art that by mixing propane-air to provide a gas of a slightly higher heating value than that required for establishing the same ignition velocity in the primary mix, the ignition velocity will be reduced appreciably, a phenomenon accomplished by only a slight decrease in port velocity. 'The decrease in ignition velocity is appreciably larger than the decrease in port velocity, so that by an increase in propane-air heating value from that necessary to obtain the same ignition velocity of the primary air-gas mix as that of the air-gas mix for which the burner was adjusted, a new slower ignition velocity which will produce the same size inner cone and the same flame stability can be obtained. The amount of decrease in propaneair heating value necessary to obtain this result can be accurately determined,

The aforementioned value of K for the gas for which this burner was originally adjusted would then be the relative value of primary air required for this last mentioned propane-air mixture (which WOllld'bB equal to the percentage value of primary air required for 8% ignition velocity) multiplied by the heating value per standard cubic foot, divided by the square root of the density, and multiplied by the air requirement per B. t. u.

Gases of like K valueswill then be interchangeable on domestic appliances in accordance with common procedure and will produce similar stable flames. This value of K is used in the calibration of the instrument herein disclosed and provides a means for calibration and design. In this instrument for indicating gas interchangeability I employ the principle of establishing a flame with a fixed size of inner cone, the size and shape of the inner cone being selected in accordance with the value of K in such a manher that the burner normally will operate with a primary air mixture which will produce an ignition velocity corresponding to that generally used on domestic appliances. cone is used as a criterion.

Referring more particularly to that form of my invention illustrated in Figs. 1, 2, and 4, the numeral I (Fig. l) designates a burner of the Bunsen type, the tube I thereof being formed of a suitable metal, such as stainless steel; the upper end portion of said tube being spun inwardly or otherwise shaped as shown at I2 to provide an opening of reduced size to slidably receive an upwardly inserted tubular metal member I3 also preferably formed of stainless steel. Member I3, which serves as the burner tip, has an outwardly extending peripheral flange |4 formed at its lower end to underlie the inner periphery of portion I2 of tube I; said tubes l3 and I I being soldered or otherwise rigidly and permanently connected with each other, as indicated at I5. The base I6 of the burner preferably consists of a cast and/0r machined member of a suitable metal, such as steel. Member I6 is formed at H to provide a seat for the lower edge of tube I I and to extend telescopically a short distance into the lower end of the latter; said parts being soldered or otherwise rigidly and permanently connected to each other, as indicated at l8.

Base member |6 has formed in the upper end portion thereof a relatively large cavity I9 which serves as a mixing chamber for the primary air and gas supplied to the burner. A circular opening 20 in the bottom wall of cavity I9 opens downwardly to a cylindrical recess 2|; base I6 having an outwardly extending flange 22 peripherally surrounding the lower portion of recess 2|. Flange 22 is provided with a multiplicity of openings to freely accommodate the shanks of screws 23, which shanks take into a corresponding number of tapped openings provided in a support plate 24, which is soldered, welded or otherwise rigidly attached to the walls of a housing the illustrated fragment of which is designated by numeral 25. A bracket 26 is attached to one wall of housing 25 and to plate 24 to assist in supporting the latter.

Slidably mounted upon the tubular connecting portion 27 of an expansible bellows type thermally responsive unit is a hollow bushing 28 internally threaded at 29, an externally threaded gland 36 having a polygonal head 3|, and a quantity of suitable packing material 32. Bushing 28 is provided at its lower end with an annular flange 33 which underlies the flange 22; flange 33 having clearance openings for, and flange 22 having tapped recesses to accommodate, the shanks of a multiplicity of clamping screws 34; a gasket 35 of rubber or rubber-like material being interposed between flanges 22 and 33 to render such connection gasand air-tight. When tubular portion 21 has been properly positioned with respect to bushing 28 (as hereinafter described), gland 30 may be driven inwardly to compress or compact the material 32 to clamp said parts in such assembled position and to likewise render the connection therebetween gasand air-tight. I

The height of the inner The upperend of tubular portion 21 extends upwardly for a substantial distance through an opening ofcorresponding size in the lower end of a substantially cylindrical container 36, as shown at 31; said parts being soldered or otherwise secured to each other as shown at 38 to pro vide a liquid-tight and pressure-resisting connection therebetween. The upper end wall 39 of container 36 is preferably of approximately cone-shape; the same having a central opening therein to closely accommodate the lower end portion of a metal member 40 of circular form in transverse cross section. Said lower end portion extends downwardly into container 36 to a point rather closely adjacent the end 31 of tubular portion 21; said lower end portion being drilled or otherwise formed with a recess 4| opening to the lower end thereof; the peripheral wall of recess 4| at the upper end thereof having one or more openings 42 formed therein within container 36 to afford direct communication between the upper end of recess 4| and the upper end portion of container 36. Wall 39 is soldered or otherwise rigidly secured to member 40 as shown at 43 to provide a liquid-tight connection between these parts.

Member 4|! is provided at its upper end with a reduced portion in the form of a threaded extension or stud 44 over which a central (threaded or clearance) opening in a spider or spacer 45 (Figs. 1 and 2) is adapted to fit. A metal probe 46, the lower end portion of which has the same diameter as member 40, has formed therein a tapped recess 41 to accommodate stud 44, whereby .probe 46 and spider 45 may be rigidly but removably secured to member 40. As best illustrated in Fig. 2, spider 45 fits closely within the tubular member I3 to center and stabilize the parts against transverse movement relatively to burner I I or the member l3 thereof. As shown at 48 probe 46 is preferably provided with a curved tapering contour from a given point to the upper end thereof; said upper end having only a. slight radius of, say, one-sixteenth of an inch or less.

The parts thus far described will be assembled in such a manner that the tip or upper end 48 of probe 46 will project upwardly a predetermined distance beyond the upper edge of burner tip 3; such distance being selected in accordance with the contemplated height of the inner cone 49 of a flame 50 to be produced by a gas to be normally supplied to the device. As aforestated, it is preferred that the tip of probe 46 shall be so located that it is just at the center of the surface or area which defines the inner cone 49 of the flame. Under these conditions a more or less constant quantity of heat will be transmitted by radiation from the inner cone of the flame to probe 46, the effect of the heat so transmitted being normally neutralized or balanced, with respect to the liquid 5| within container 36, by the flowing mixture of primary air and gas upwardly through burner II to the point of combustion at the burner tip I3; as hereinafter more fully described.

The aforementioned tubular connecting portion 21 communicates at its lower end with the interior of an expansible and contractible bellows, which is shown at 52 as having corrugations in the vertical peripheral wall thereof. Bellows 52 has its lower end wall soldered, brazed or otherwise rigidly secured to the bottom wall of a cup-shaped housing member 53, as shown at 54; said housing member having an externally threaded nipple 55 formed thereon. Nipple 55- hasa central opening, formed by a reentrant flange 56, to accommodate said tubular portion 21; the latter being soldered or otherwise rigidly secured to nipple 55 as indicated at 51.

Nipple 55 extends downwardly through a suitable opening in the horizontal portion of a bracket member 58, one vertical arm 59 of which is secured to an inwardly offset vertical wall portion 89 of housing 25, as by means of a screw 6|; the other vertical arm 62 of bracket 58 being secured by a pair of screws BI to the opposite inwardly offset vertical wall portion 63 of housing 25. Arm 92 of said bracket is provided at its upper end with an inwardly extending horizontal portion 54, to which a cantilever type spring 95 and another bracket member 66 are attached, as by means of a pair of screws 61. The use of spring 95 provides an important advantage over the conventional type of pivot, in that it affords a frictionless oscillatable connection, and a fixed relationship is thereby insured between the axis of the valve member 83 and the valve seat or opening 81 hereinafter described.

Spring 95 has rigidly and permanently attached to the free end portion thereof, as by means of a plurality of rivets 89, a sheet metal lever member 69, between which and an upwardly offset portion 19 of bracket 85 a coiled compression spring 1| is interposed. Spring 1I serves to load lever 69 and to yieldably resist upward displacement thereof as an incident to expansion of bellows 52 by the effect of heat upon the liquid within the latter. For this purpose bellows 52 has attached to the upper end thereof a disk or plate 12 carrying centrally thereof a stud or pin 13, the cone-shaped upper end 14 of which is adapted to bear within a recess (not shown) formed in the lower surface of a metal member 15 carried by lever 59.

A nut 16 which is captive upon the aforementioned tubular portion 21 is adapted to cooperate with nipple 55 to clamp the aforementioned housing member 53 to bracket member 58. Attached to the upper end of member 53 is a metal cover plate 11; the latter having a central opening to provide operating clearance for stud 13, and said cover plate preferably having a downwardly extending circular rib 18 formed thereon for cooperation with plate 12 to limit the maximum degree of upward movement of stud 13.

Lever 69 has formed integrally therewith an upstanding lug 19, to which a relatively long pointer 89 may be attached at the point and at the angle indicated, as by means of rivets 8I'. Pointer 89 is adapted to cooperate with a suitable stationary scale 82 which may be calibrated in any suitable or desired manner to afford an instantaneous and continuous indication of the interchangeability characteristics of the gas supplied to the device; as, for instance, by applying percentage values of to 50 per cent on each side of the intermediate or zero value illustrated.

Removably attached to the right-hand end of lever 89 is a movable valve member 83 which is preferably in the shape of a frustum of a cone; said valve member having a threaded stud 84 extending downwardly through a suitable opening in lever 99 for cooperative engagement by a clamping nut 85. The stationary portion of the valve comprises a cup-shaped metal member 86 having a centrally located circular opening 81 formed in the bottom wall thereof; said opening having a downwardly and outwardly beveled edge as shown to provide for complete closure thereof in the upper extreme position of valve member 83, and to provide for a gradual increase in the annular area of the opening upon downward movement of member 83.

Member 86 fits closely around the open lower end of a relatively short tube 88, and is secured to the latter as by means of a set screw 89. The reduced upper end 99 of tube 88 fits within an opening of corresponding size formed in a metal member 9|; tube 88 being rigidly secured in position, as by means of a ring of solder, as indicated at 92. The bracket member 96 is also rigidly and permanently attached to member 9I by soldering or the like, as indicated at 93.

Member 9| is provided with a relatively large recess 94 and a flared neck or passage leading therefrom to the aforementioned recess I9. The material surrounding neck 95 has an end portion fitted into a correspondingly shaped opening in member I8, and is soldered or otherwise secured thereto as shown at 96. An externally threaded nipple 91 penetrates an opening in the wall of recess 94 and is soldered or otherwise rigidly secured to said wall, as indicated at 98. Nipple 91 is provided with kerfs 99 and I99 extending downwardly throughout the major portion of the length thereof, and an internally threaded cap I9I is manually adjustable with respect thereto to provide for variation between zero and a predetermined maximum value the amount of air which may be drawn through nipple 91.

An injector nozzle I92 is positioned within recess 94, said nozzle being centrally alined with respect to the tapered passage or neck 95, and the tip I93 of the nozzle being ad'justably positioned at the desired point with respect to the entrance to passage 95. The means affording such adjustment of nozzle I92 comprises a threaded portion I94 thereon which takes into a tapped opening I95 in the reduced portion I96 of a hollow metal supporting member I91; said reduced portion I96 fitting into an opening provided in the walls of recess 94, and being soldered or otherwise rigidly attached thereto, as shown at I98. The hollow rear end portion I99 fits closely but rotatably and slidably within the rear end portion I I9 of member I91; a part of portion II9 being reduced and externally threaded as shown to permit the same to penetrate an opening III provided in the angular wall portion II2 of housing 25. A pair of gaskets H3 and H4 is arranged on opposite sides of wall portion H2, and a suitable internally threaded metal cap I I5 cooperatively engages the thread on reduced portion I I9 to clampingly engage the gasket I I4 and thus afford a gas-tight seal for the open rear end of nozzle I92. Member I91 is provided with a recess II6 surrounding a part of the length of portion I99 of the nozzle, the part thus surrounded preferably having a pair of transverse passages II1 and H8 drilled therethrough to afford communication between recess H6 and the longitudinal passage through the nozzle. The rear end of the nozzle is provided with a kerf I I9 or other means to provide for removal of nozzle I92 for cleaning the same or substituting another jet therefor; the cap II5 being removed.

Member I91 is provided with a tapped opening I29 communicating with recess 9; a nipple I2I being threaded thereinto to provide a gas-tight connection for one end of a relatively small pipe or conduit I22 by which a gas sample is supplied to the injector nozzle I92. Any suitable means (represented diagrammatically at I22 may be provided for insuring the desired pressure of the gas sample supplied through'pipe I22.

As will be noted the lever 68 (Fig. 1) is provided with a second bearing member I23 similar to that shown at I5. The recess in the lower surface of member I23 is adapted to accommodate and engage the conical upper end I24 of a short rod I25 having attached thereto a nut I26 which is adapted to accommodate more or less of the tapped end I 21 of a relatively longer rod I 28, only a fragment of which is shown in Fig. 1. Another portion of rod I28 is shown in Fig. 4 as having its conical lower end I29 bearing in a member I30 carried by a lever I3I which is shown as pivoted at I32; a downwardly extending portion I33 of which lever is shown as provided with a pen I34 for effecting a graphic indication upon a movable recording chart I35. I In the particular form shown, the chart I35 is adapted to simultaneously provide for recording of the instantaneous total heating value per unit volume of the gas sample, as by means of the pen I36 which may be operated by means well known in this art. Where both total heating value and interchangeability characteristics of the gas are to be recorded, it is to be understood that chart I35 will be specially calibrated to afford the proper record of interchangeability. The indicator I31 in Fig. 4 is adapted to micrometrically indicate the instantaneous total heating value of the gas in conjunction with the peripheral scale I38, which may have suitable heating value numerals (not shown) applied thereto.

The operation of the device shown in Figs. 1, 2 and 4 is as follows: Upon connection of conduit I 22 to a source of supply of the gas at a constant pressure and upon ignition of the mixture of gas and primary air at the tip I3 of the burner, fixed combustion zones will result, depending upon the composition of the gas and adjustments of the equipment. When the mixture of gas and primary air is first ignited to provide the burner flame the various parts of the equipment, including the bulb or container 36 and the body of liquid 5| may be assumed to be at room temperature. The valve member 83 will then'be at approximately its maximum lowered position, so that the amount of induced air will be at a maximum. With a gas composition such that the equipment is adjusted within the operating range, the percentage value of primary air will be high enough to produce a small inner cone flame, the tip 48 of probe 46 projecting a substantial distance into the primary combustion zone, or inner cone.

Heat from the primary combustion zone is therefore rapidly conducted through probe 46, rod 48 to hollow portion M of the latter, and from rod 40 to bulb or container 36, though the portion 39 of the latter. Portion M and container 36 transmit this heat to the liquid 5|, raising the temperature of the liquid, and therefore increasing the vapor tension of the liquid in bulb 36, In addition to the heat transmitted to probe tip 48 by direct contact with said combustion zone of the inner cone of the flame, some heat is also transmitted by radiation from the flame to the associated parts.

As the temperature of the bulb 36 and the lower portion of probe 46 and rod 40 increases, the difference in temperature between the incoming relatively cool primary air-gas mixture and bulb 36 produces a cooling effect on said bulb, thus tending to counteract the temperature increase of the bulb. With the probe tip 48 projecting,

into the combustion zone of the inner cone as aforementioned heat is transmitted to the bulb 36 and liquid 5I at a high rate of speed, as compared with the rate at which heat is removed from said bulb and liquid by the cooling effect of the primary air-gas mixture flowing upwardly therealong, so that the temperature and vapor tension of the liquid in the bulb will rise. The increase in vapor pressure in bulb 36 is transmitted through the liquid 5| in tube 21 to bellows element 52, thus extending or expanding the latter in opposition to the force of spring II and causing arm 69 to move in a counterclockwise direction with respect to the aforementioned point of oscillation 65.

The accompanying partial closure or reduction in size of the area between valve member 83 and the periphery of valve opening 81 restricts the flow of primary air to the burner II, thereby reducing the percentage of primary air in the gasair mixture; thus lowering the ignition velocity of the mixture. Although this reduction in ignition velocity is accompanied by a decrease in total flow from the burner tip I3, this latter change is small as compared with the change in ignition velocity, and therefore the inner combustion zone extends itself until the same has risen above the tip 48 of the probe. With the inner cone above the tip 48 of the probe only radiant heat can reach the thermometer bulb, whereas the effect of this radiant heat is substantially neutralized by the cooling effect of the comparatively cool primar air-gas mixture flowing in contact with the bulb and probe.

The temperature of the liquid 5I in bulb 36 will therefore drop quite rapidly, the consequent reduction in vapor pressure of the liquid permitting lever 68 to move in a clockwise direction due to the force exerted b spring II. The ignition velocity is' therefore increased until the inner cone (49) of the flame engages the tip of the probe, at which time the rate of heat transfer to the'bulb increases rapidly. Sequential heating and cooling of the bulb incidental to engagement and disengagement of the probe tip with the inner combustion zone establishes an average rate of heat transfer to the bulb at a value which will maintain valve member 83 in such a position that the inner cone 49 of the flame will just touch the probe tip 48.

As will be apparent, there is a distinct and wide difference in temperature between points infinitesimal distances respectively below and above the inner combustion zone, and that therefore an infinitesimal change in height of the inner cone will result in an extremely large change in rate of heat transfer to the bulb and liquid 5|, wherefore the actual temperature used to position valve member 83 and thus control the height of inner cone 49 is of relatively slight importance. For example, if the force applied by spring II were doubled by adjusting the same or increasing its strength or caliber, so that the thermometer bulb 36 and liquid 5I would have to be at a very much higher temperature, valve member 83 would nevertheless assume substantially the same position under the aforedescribed conditions; because, although the inner cone would have to be at an infinitesimally lower average position, this difference in height of the inner cone is insignificant in the practical measurement. Similarly, if gas compositions should differ, to cause a different positioning of valve 83 and therefore requirea different bulb temperature, the average height of cone 4!! would be established at the same position. From the foregoing it is obvious that the relative position of valve member 83 and lever 69 supporting the same will indicate the degree of adjustment of the supply of primary air required to maintain the inner combustion zone 45 at a substantially constant position. Gases which produce the same positioning of lever 65 will therefore be interchangeable in respect of maintaining a predetermined height of the inner cone and insuring stability of the flame on burners of similar construction.

As aforeindicated, the calibration of the device may be changed when in use to accommodate various substantially different types of gases (as, for instance, changing from gases having high values of the factor K to gases having low values of the factor K) by proper adjustment of cap IIH to vary the amount of primary air supplied to a substantially fixed degree, and/or by substituting for member 86 a member having a valve opening which is either larger or smaller than the opening 81 aforedescribed.

In practice the housing 25 is provided with a front plate or cover (not shown) to substantially completely enclose the device, whereby the effect of drafts of ambient air upon the burner flame is minimized; said housing being also preferably provided in its upper end wall (not shown) with a pipe or conduit which serves as a flue the combustion products released by the burner flame. It is to be understood, however, that the interior of housing 25 will have sufficient access to the surrounding air to insure the required amount of primary air and an adequate amount of secondary air for combustion with the gaseous mixture at the burner tip. In some installations, however, it may be desirable to seal off the housing 25 from the ambient air (the fiue being suitably connected with a smoke-stack or the like for disposal of the combustion products); in which case a special supply of air will be fed by conduit to the housing to provide a sufficient quantity of primary and secondary combustion air. Such an arrangement is desirable where the ambient air may possibly be of combustible character.

In the modification illustrated in Fig. 3, the parts I3, 46 and 45 may be identical with the corresponding parts aforedescribed. In Fig. 3, however, the probe I31 is of special form, the same preferably being tapered somewhat and having a blunt or hemispherical tip I38 and a solid disk I 39 concentric with and spaced downwardly a substantial distance from said tip. The primary effect of disk I39 is to substantially widen and flatten or blunt the upper end portion I40 of the inner cone I4I of flame I42. The redistribution of the inner cone in this manner is desirable with gases having a high value of K, where the inner cone would normally become large and therefore considerably elongated; thus rendering it difiicult to provide the zones of distinctly different temperatures in proper operative relationship to the tip of the probe. Conversely, upon an increase in height of inner cone I4I with respect to probe I38, the combustion zone of said inner cone will be spaced a greater distance than normal from both the tip I38 and the periphery of disk I35. By this means the sensitivity of the device as a whole to variations in the interchangeability factor K of the test gas may be increased.

In Fig. 5 I have shown, slightly more diagrammatically, an adaptation of my invention to the distant indication and recordation of variations in the interchangeability characteristics,

or factor K, of a continuous test sample of gas. Thus whereas I have shown in Fig. 5 only that part of tubular portion 21 which communicates with bellows 52, it is to be understood that the upper part of tube 21 will be connected with the container 36 in the manner illustrated in Fig. l, and that the various other parts of the burner may be the same as those shown in Fig. 1. The pointer 86a in Fig. 5 is substantially like that shown at in Fig. 1; the cooperating scale 82 being the same in both figures. The parts 65*, 19 and 69 shown diagrammatically in Fig. 5 may correspond exactly with the parts 65, 19 and 69 in Fig. 1. The parts 83, 86, 81 and I25 in Fig. 5 are also preferably identical with the correspondingly designated parts in Fig. 1.

In Fig. 5, however, I have shown a follow-up lever I43 which is fixedly pivoted upon a pin I44, such point of pivotal support of lever I43 preferably being concentric with the center of oscillation of pointer arm as represented at 65 in Fig. 5' by the point of bending of cantilever spring 65 in Fig. 1. Lever I43 has attached to its upper end a jet I45, which is connected by a flexible conduit I46 with a conduit I41 to which air, for instance, is supplied through a fixed orifice I48 and a pressure regulator I46 from a suitable source of compressed air as represented by the arrow I50. Conduit I41 likewise communicates, through branch I5I, with the interior of an expansible metal bellows I52, the rear end of which is rigidly attached to a fixed bracket I53 and the free end of which carries a stud I54 which continuously bears against the left-hand side of the lower end I55 of lever I43. A coiled compression spring I56 is interposed between the right-hand side of the lever end I55 and a second arm I51 of bracket I53.

The pointer 66 has attached thereto a flap or closure member I58 which is adapted for cooperation with the open end of jet I45, to effect closing of the latter or opening thereof to a variable degree (for bleeding of the air and reduction of pressure within conduit I41) according to the relative positions of pointer 85 and said follow-up lever I43.

Conduit I41 also communicates, through branch I59, with a Bourdon tube I66 which responds to variations of pressure within conduit I41; said Bourdon tube I65 having the usual indicating arm I6I which is adapted for cooperation with a suitable scale I62, which may have legends exactly corresponding with those employed on scale 82. The Bourdon tube I66 may thus act to afford a distant indication of the interchangeability characteristics of the gas, as indicated locally by the pointer 86 and scale 82.

Conduit I41 further communicates, through branch I63, with the interior of an expansible metal bellows I64, the rear end of which is attached to a bracket I65 attached to the wall of a recorder housing I66; the free end of bellows I64 having a stud I61 which continuously engages the left-hand side of the lower end I66 of a lever pivoted at I66; a coiled compression spring I16 being interposed between the righthand side of lever end I63 and another wall of housing I66. The upper end I1I of said lever carries a pen or marker I12 which is adapted to cooperate with an automatically movable chart I13 to afford a continuous record I14 of the interchangeability characteristics of the test gas.

The operation of the pneumatic distant indicating and recording system shown in Fig. 5 is as follows: As the pointer 80 moves toward the right (or, in a clockwise direction) the amount of bleeding of air (entering through the supply regulator I49 and orifice I48) as jet I45 increases, thus reducing the pressure in the conduit I41 and its branches II, I59, and I63. The spring I56, which biases follow-up lever I43 to move in a clockwise direction is opposed to the force applied to said lever by bellows I52, and said spring I 56 has a relatively steep pressure characteristic. That is to say, the force of spring I56 increases rapidly as the follow-up lever I43 moves in a counterclockwise direction, whereby the same exerts a predetermined force in each different position of said lever. To position said follow-up lever it is therefore necessary that the fluid pressure within bellows I52 shall exert a force equal to the force of spring I56, so that for each position of said lever there will be a predetermined pressure in said bellows. This same fluid pressure is transmitted through the branch conduits to the recording meter Hi5 and the indicating gauge I60. The fluid pressure in the devices last mentioned is opposed by springs (the spring I in recorder I66 and the Bourdon tube in gauge I60) of equivalent or corresponding force, so that the movable element of said devices may assume definite or predetermined positions for each different pressure of the fluid. The arrangement is such that jet I45 is completely closed when the flapper or plate I58 is against the tip of said jet. amount of movement of flapper away from the jet allows air to flow from the jet, thus relieving the pressure in the system and causing the spring I56 to move the follow-up lever I43 in a clockwise direction to again tend to close on the flow from the jet. In this new position of lever I43 less fluid pressure will be required in the system to balance the spring I56, so that the distance between the jet and the flapper will be an infinitesimal amount greater than in the first instance, because an opening of infinitesimal size is sufficient to bleed off air at a rate which will reduce the pressure by an appreciable amount, to thereby establish the new pressure required to balance the spring I56. The pressure regulator I69 in the air supply to the system is preferably set to maintain a pressure slightly higher than the pressure required to move the follow-up lever to the end of the scale in the counterclockwise direction. With the jet I45 entirely closed off, this pressure will then be established in the system, and the recorder I66, gauge I60 and followup lever M3 will be in the sub-zero position,

With the aforedescribed gas interchangeability determining device (Fig. 1) reading zero, air would then escape from the jet I45, causing the follow-up lever I43 to move up on the scale 82 (that is, toward the left) to a point where the leakage of the jet is reduced to a value which will establish the pressure required to balance the follow-up lever I43 and bring the jet substantially in contact with the flapper. As the indication of the gas interchangeability determining device increases and arm 80 moves toward the right, performance is similar, the follow-up lever 243 following the movement of the arm 80, except that the gap between-the jet I45 and flapper I58 increases (indicated by arm (I0 on scale 82) becomes higher. For all practical purposes the follow-up lever I43 maintains the same. relative position, as the arm An extremely small slightly as the value of factor K 80. Inasmuch as the spring loading characteristics of the recorder I66, indicating gauge I and follow-up lever I43 are similar in respect of their scale readings, corresponding positions will be assumed by these devices, and distant indication and recordingof the same value indicated locally by arm and scale 82 will be obtained.

I claim:

The method of measuring gas interchangeability in a device of the Bunsen burner type, which comprises normally subjecting a heat conducting thermometric probe to the temperature of the primary air-gas flow immediately ahead of the primary combustion zone as a measure of the height of theinner cone of the flame, whereby the probe is rendered extremely sensitive to variations in the height of said inner cone, effecting adjustment of the-primary air flow to the burner asa'function of the rate of transfer of heat to the probe in a mannerto counteract variations in the height of said inner cone and utilizing the setting of said primary air adjustment as an indication of a property of the gas definitely related to gas interchangeability.

2. The method of measuring the degree of interchangeability of a gas, which comprises supplying a continuous sample of said gas at a substantially constant pressure to a burner of the Bunsen type, utilizing said flow of gas to normally effect injection into said burner of a predetermined proportional flow of primary air for mixture with said gas, igniting said mixture of gas and'primary air at the burner tip to provide a flame the inner cone of which is normally of predetermined height, positioning a heat conducting thermometric probe at the desired point of the combustion zone atthe tip of said inner cone, said probe being thermally responsive to movement of said combustion zone above and below the upper end of the probe to generate a source of power of correspondingly variable value, utilizing the variable value of the generated power to effect variation of the proportionality of said flow of primary air, whereby said inner cone is maintained at substantially said predetermined height, and measuring and indicating the amount of variation in the proportionality of said flow of primary air so effected.

3. The method of measuring the degree of interchangeability of a gas, which comprises supplying a continuous sample of said gas at a substantially constant pressure to a burner of the Bunsen type, utilizing said flow of gas to normally efi'ect injection into said burner of a predetermined proportional flow of primary air for mixture with said gas, igniting said mixture of gas and primary air at the burner tip to provide a flame the inner cone of which is normall of predetermined height, positioning a heat conducting thermometric probe at the desired point of the combustion zone at the tip of said inner cone, said probe being thermally responsive to movement of said combustion zone above and below the upper end of the probe as an incident to variations in the ignition velocity of said mixture of gas and primary air to generate a source of power of correspondingly variable value, utilizing the value of the generated power to effect variation of the proportionality of said flow of primary air, whereby said inner cone is maintained at substantially said predetermined height,- measuring. the amount of variation in the proportionality of said flow of primary air so effected, and utilizing said measurement as an indication of the degree of interchangeability of said gas with respect to a gas of known combustion characteristics.

4. In combination, a Bunsen type burner, means for supplying gas at a constant pressure to the jet of the burner, means including an adjustable valve for controlling the induced flow of primary air to said burner, the mixture of gas and air being ignited in the presence of secondary air to provide a flame, a heat conducting probe arranged in a fixed position normally slightly below the tip of the inner cone of said flame so that the rate of heat transfer to the probe changes rapidly with a small increase or decrease in the height of said inner cone of the flame, means including an expansible medium associated with said probe and responsive to the heat conducted by the latter for eiiecting variation in the positioning of said adjustable valve, and means associated with said valve for indicating the degree of interchangeability of said gas with a gas of known combustion characteristics.

5. In combination, a Bunsen type burner, means including a jet for supplying thereto a continuous flow of gas at a predetermined constant pressure, means including an adjustable valve for permitting induction of primary air to said burner by the injector effect of said flow of gas, a thermometric probe positioned within the tube of said burner and projecting upwardly a substantial distance beyond the burner tip, the tip of said probe being located in line with and at the top of the inner cone of the burner flame in the normal condition of the 1atter, and said probe being thermally responsive to variations in the height of said inner cone to effect corresponding adjustments of said valve, whereby the height of said inner cone is maintained substantially constant.

6. In combination, a Bunsen type burner, means including a jet for supplying thereto a continuous flow of gas at a predetermined constant pressure, means including an adjustable valve for permitting induction of primary air to said burner by the injector efiect of said flow of gas, a thermometric probe positioned within the tube of said burner and projecting upwardly a substantial distance beyond the burner tip, the tip of said probe being located in line with and at the top of the inner cone of the burner flame in the normal condition of the latter, said probe being thermally responsive to variations in the height of said inner cone to efiect corresponding adjustments of said valve, whereby the rate of supply of primary air to said burner is varied, to thereby maintain substantially constant the height of said inner cone, and associated means movable with said valve to directly indicate the degree of interchangeability of said gas with respect to a gas of known combustion characteristics.

'7. In combination, a burner of the Bunsen type. means including a jet for supplying thereto a continuou flow of gas at a predetermined constant pressure, means including an adjustable valve for permitting induction of primary air to said burner by the injector effect of said flow of gas, a thermometric probe positioned within the burner tube and projecting upwardly a substantial distance beyond the burner tip, said probe being located in line with and at the top of the inner cone of the burner flame in the normal condition of the latter, said probe having associated therewith a bellows System including a container located within the burner tube, a belthe tip of lows located exteriorly of said burner tube, a conduit ailording communication between said container and said bellows, and a common body oi vaporizable liquid substantially filling said container, said bellows and said conduit, whereby said liquid is thermally responsive to variations in the height of said inner cone to provide for corresponding degrees of expansion or contraction of said bellows, said bellows having a movable part thereof associated with said valve to provide for corresponding movements of the latter whereby the proportionality of the amount of primary air induced into said burner is varied, to thereby maintain substantially constant the ignition velocity of the mixture of gas and pri mary air and the height of said inner cone, a pointer movable with said valve, and a suitably calibrated scale associated with said pointer, whereby the degree of interchangeability of said gas with respect to a gas of known combustion characteristics is indicated.

8. In a device for measuring the degree of interchangeability of a gas with respect to another gas of known combustion characteristics, in combination, a Bunsen type burner, means including a nozzle for continuously supplying a flow of gas at a predetermined pressure to said burner, associated means for controlling the total amount of primary air induced into said burner by said flow of gas through said nozzle, said last mentioned means including a valve associated with said burner and having an element thereof springbiased to a given position, a thermometer including a probe the upper end of which is located at the normal tip of the inner cone of the burner flame, and means associated with said probe and adapted to act against the spring-bia of said valve element to maintain the latter in a predetermined position so long as the inner cone of said flame is of a given normal height, the arrangement being such as to insure a predetermined rate of opening or closing movement of said valve element as an incident to an increase or decrease, respectively, in the height of said inner cone with respect to the normal height thereof.

9. In a device for measuring and indicating the degree of interchangeability of a gas with respect to another gas or gases of known combustion characteristics, in combination, a Bunsen type burner, means including a nozzle for continuously supplying a flow of gas at a predetermined pressure to said burner, associated means for controlling the total amount of primary air induced into said burner by said flow of gas through said nozzle, said last mentioned means including a valve associated with said burner and having an element thereof spring-biased to a given position, a thermometer including a probe the upper end of which is located at the normal tip of the inner cone of the burner flame, means associated with said probe and adapted to act against the springbias of said valve element to maintain the latter in a predetermined position so long as the inner cone of said flame is of a given normal height, the arrangement being such as to insure a predetermined rate of opening or closing movement of said valve element as an incident to an increase or decrease, respectively, in the height of said inner cone with respect to the normal height thereof, and means including a pointer movable with said valve element in one direction or the other, said pointer having a suitable scale associated therewith whereby the degree of interchangeability of said gas is indicated.

fiow of gas, said last 10. In a gas interchangeability measuring device, in. combination, a'Bunsen type burner, a thermometer including a probe the upper end of which is located at the normal tip of the inner cone of the burner fiame,; said thermometer also including a bellows system and a vaporizable liquid contained therein, means for supplying a'continuous and substantially constant flow of gas to said burner, associated means for controlling the total amount of air induced into said burner by said flow ofgas, said last mentioned means including a valve spring-biased to a given position, the pressure of vapor within said bellows system acting against the spring-bias of said valve to maintain the latter in a predetermined position so long as the inner cone of said flame is of a given normal height, and the arrangement being such as to insure apredetermined rate of decrease or increase in said vapor pressure as an incident to an increase or decrease, respectively, inthe heightof said inner cone with respect to said normal height thereof. V y r 11. In a gas interchangeability measuring device, in combination, a Bunsentype burner, a thermometer including a probe the upper end o f which isllocated at the tip of theinner cone of the burner fiame said thermometer also including a bellows system and a vaporizable liquid contained therein, means for supplying at a predetermined pressure a continuous flow of gas to said burner, associated means for controlling the total amount of air induce into said burnerby said flow of gas, said last mentioned mean including a valvespring-biased to a given position, the pressure of vapor within said bellows system acting against the spring-bias of said valve to maintain the latter in a predetermined position so long as the inner cone of said flame is of a given normal height, the arrangement being such as to insure a predetermined rate of decrease or increase in said vapor pressure as an incident to an increase or decrease, respectively, in the height of said inner cone with respect to said normal height thereof, and associated means for indicating the degree of movement of said valve in one direction or the other from said predetermined position thereof.

12. In a gas interchangeability measuring device, in combination, a Bunsen type burner, a thermometer including a probe the upper end of which is located at the tip of the inner cone of the burner flame, said thermometer also including a bellows system and a vaporizable liquid contained therein, means for supplying at a predetermined pressure a continuous flow of gas to said burner, associated means for controlling the total amount of air induced into said burner by said mentioned means including a valve spring-biased to a given position, the pressure of vapor within said bellows system acting against the spring-bias of said valve to maintain the latter in a predetermined position so long as the inner cone of said flame is or a given normal height, the arrangement being such as to insure a predetermined rate of decrease or increase in said vapor pressure as an incident to an increase or decrease, respectively, in the height of said inner cone with respect to said normal height thereof, and associated means for indicating the degree of movement of said valve in one direction or the other from said predetermined position thereof, said last mentioned means being calibrated to indicate the degree of departure of the combustion characteristics of said gas from a value of perfect interchangeability with respect to a gas of known combustion characteristics.

1 13. In a gas. interchangeability measuring device, in combination, a Bunsen type burner, means'forv supplying a continuous flow of gas thereto, means including a valve for normally providing a substantially constant fiow of air for mixture with said gas, said mixture of gas and air when ignited at the burner tip being adapted to normally provide a flame having an inner cone of predetermined height, a probe supported by said burner and having its tip locatedadjacent the tip of said inner cone, means comprising a container including an expansible bellows, .a quantity of vaporizable liquid within said container, an oscillatable support for said valve, said bellows being arranged on one side of said supporttobias said valve in one direction and a spring for biasing said valve in the opposite direction, the quantity of heat transmitted from said inner cone to said probe being adapted to provide a balancing effect of said bellows against said spring wherebysaid valve is maintained in a predetermined position, the arrangement being such that the biasing eifect of said bellows is decreased upon an increase in the height of said inner cone and increased upon a decrease in the height of saidcone with respect to the normal height thereof, to thereby eiiect adjustments of said valve, and means associated with said valve to indicate the degree of adjustment thereof in either direction from its said predetermined posi- .tion.

14. In a gas interchangeability measuring device, in combination, a. Bunsen type burner, means for supplying a continuous flow of gas thereto, means including a valve for normally providing a substantially constant flow of air for mixture with said gas, said mixture of gas and air when ignited at the burner tip being adapted to normally provide a flame having an inner cone of predetermined height, a probe supported by said burner and having its tip located adjacent the tip of said inner cone, means comprising a container including an expansible bellows, a quantity of vaporizable liquid within said container, an oscillatable support for said valve, said bellows being arranged on one side of said support to bias said valve in one direction and a spring for biasing said valve in the opposite direction, the quantity of heat transmitted from said inner cone to said probe being adapted to provide a balancing effect of said bellows against said spring whereby said valve is maintained in a predetermined position, the arrangement being such that the biasing effect of said bellows is decreased upon an increase in the height of said inner cone and increased upon a decrease in the height of said cone with respect to the normal height thereof, to

thereby eflect adjustments of said valve, means associated with said valve to indicate the degree of adjustment thereof in either direction from its said predetermined position, and said last mentioned means being calibrated to indicate the degree of interchangeability of said gas with a gas of known combustion characteristics.

15. In a gas interchangeabilit measuring device, in combination, a Bunsen type burner, means for supplying a continuous fiow of gas thereto, means including a valve for normally providing a substantially constant new of air for mixture with said gas, said mixture of gas and air when ignited at the burner tip being adapted to normally provide a flame having an inner cone of predetermined height, a probe supported by said burner and having its tip located adjacent the tip of said inner cone, means comprising a container including an expan'sible bellows, a quantity of vaporizable liquid within said con tainer, an oscillatable support for said valve, said bellows being arranged on one side of said support to bias said valve in one direction and a spring for biasing said valve in the opposite direction, the quantity of heat transmitted from said inner cone to said probe and the rate of dissipation of heat from the latter and from the liquid within said container being such'as to provide a balancing effect of said bellows against said spring whereby said valve is maintained in a predetermined position, the arrangement being such that the biasing effect of said bellows is decreased upon an increase in the height of said inner cone and increased upon a decrease in the height of said cone with respect to the normal height thereof, to thereby effect adjustments of said valve, means associated with said valve to indicate the degree of adjustment thereof in either direction from its said predetermined position, and said last mentioned means being calibrated to indicate the degree of interchangeability of said gas with a gas of known combustion characteristics.

16. In a gas interchangeability measuringdevice, in combination, a Bunsen type burner, means for supplying a continuous flow of gas thereto, means including a valve for normally providing a substantially constant flow of air for mixture with said gas, said mixture of gas and air when ignited at the burner tip being adapted to normally provide a flame having an inner cone of predetermined height, a probe supported by said burner and having its tip located adjacent the tip of said inner cone, means comprising a container including an expansible bellows, a quantity of vaporizable liquid within said container, an oscillatable support for said valve, said support including a spring of the cantilever type, said spring providing a frictionless connection and insuring definite positioning of the valve with respect to its seat, said bellows being arranged on one side of said support to bia said valve in one direction and a spring for biasing said valve in the opposite direction, the quantity of heat transmitted from said inner cone to said probe and the rate of dissipation of heat from the latter and from the liquid within said container being such as to provide a balancing efiect of said bellows against said spring whereby said valve is maintained in a predetermined position, the arrangement being such that the biasing effect of said bellows is decreased upon an increase in the height of said inner cone and increased upon a decrease in the height of said cone with respect to the normal height thereof, to thereby effect adjustments of said valve, means associated with said valve to indicate the degree of adjustment thereof in either direction from its said predetermined position, and said last mentioned means being calibrated to indicate the degree of interchangeability of said gas with a gas of known combustion characteristics.

EDWIN X. SCHMIDT. 

